That was a visual I didn't need... Yeah, floating the feedback connection can cause all sorts of problems
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| Author: | Grover Gardner [ October 9th, 2018, 10:53 pm ] |
| Post subject: | Breadboard disaster? |
So I decided to breadboard the "Musicians Amplifier" because I had all the components. https://www.google.com/url?sa=t&source= ... 4sADn0VS0Q It's a very basic, "unimproved" Williamson circuit. I substituted 1625's and 12SN7's because I had the 1625's and they are 12v filaments. The original design calles for a Peerless S-265-Q. I have a pair of Pacific Transformer Peerless 16309 clones made for a Heathkit W5. My understanding is that they are electrically similar, certainly 10K P-P. Everything was according to the schematic, within 10 percent. I got oscillation for days. And no, it wasn't phase because I reversed the OPT leads and the problem remained. I think I had the phase right to begin with. So I'm asking the old hands--what happened? RF? Lousy breadboard wiring with no shielding? OPT not within spec? I'm just curious because I think it would sound lovely but I can't tell! |
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| Author: | Grover Gardner [ October 10th, 2018, 11:28 am ] |
| Post subject: | Re: Breadboard disaster? |
NEVER MIND. I was standing in the shower this morning and realized I forgot to ground the OPT secondary. Back to the breadboard! |
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| Author: | Roscoe Primrose [ October 10th, 2018, 11:31 am ] |
| Post subject: | Re: Breadboard disaster? |
That was a visual I didn't need... Yeah, floating the feedback connection can cause all sorts of problems
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| Author: | TubeDriver [ October 10th, 2018, 4:17 pm ] |
| Post subject: | Re: Breadboard disaster? |
It is sort of funny to think that you realized this in the shower and not while you were peering at the breadboard circuit! Grover Gardner wrote: NEVER MIND. I was standing in the shower this morning and realized I forgot to ground the OPT secondary. Back to the breadboard!
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| Author: | tomp [ October 10th, 2018, 6:20 pm ] |
| Post subject: | Re: Breadboard disaster? |
Showers have a habit of washing away the clutter. |
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| Author: | Grover Gardner [ October 11th, 2018, 10:26 pm ] |
| Post subject: | Re: Breadboard disaster? |
Well, it certainly did the trick this time. The shower--and grounding the output.
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| Author: | Grover Gardner [ October 11th, 2018, 10:27 pm ] |
| Post subject: | Re: Breadboard disaster? |
TubeDriver wrote: It is sort of funny to think that you realized this in the shower and not while you were peering at the breadboard circuit! Grover Gardner wrote: NEVER MIND. I was standing in the shower this morning and realized I forgot to ground the OPT secondary. Back to the breadboard! I think walking away from it for 12 hours helped.
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